Should be ok as long as you're in an open area. Carbon monoxide poisoning is probably the greatest of your concerns here.

Otherwise... Just think of it as being stuck in traffic for 8 hours. AFAIK some long-haul truckers in the US of A have their rigs running for as much as 48 hours non-stop! When they take a break (bed inside the big cab), engine is left on for A/C or heater.

We have a conversion van that comes with a power sofa/bed inside, TV, VCR and inverter. No problems idling for extended periods, but then it was probably designed that way.